Cold cathode discharge display apparatus

ABSTRACT

A cold cathode discharge display apparatus in which a main electrode whose anode consists of a plurality of electrodes while whose cathode is of a plate having a plurality of perforations for discharge space, and a trigger electrode are provided the trigger electrode consisting of a first electrode group for column and a second electrode group for raw, whereby in the display or write operation, a voltage lower than firing voltage but higher than a voltage for sustaining a discharge is applied between the main electrodes and at the same time a drive voltage is applied between the trigger electrodes while in the read-out operation, a voltage lower than firing voltage but higher than the voltage for sustaining the discharge is applied between the trigger electrodes.

Sasaki et al.

[ COLD CATHODE DISCHARGE DISPLAY APPARATUS [75] Inventors: RentaroSasaki; Akinori Watanabe,

both of Takasaki; Tatsu'o Ogasawara, Tokyo, all of Japan [73] Assignees:Oki Electric Industry Co., Ltd.;

Okaya Electric Industry Co., Ltd., both of Tokyo, Japan [22] Filed: May18, 1973 [21] Appl. No.: 361,423

[30] Foreign Application Priority Data May 25, 1972 Japan 47-051238 [52}US. Cl 315/169 R, 313/220, 313/302, 315/21 R [51] Int. Cl. H0lj 29/70[58] Field 01 Search 315/21 R, 12 FTD; 313/71, 313/70 R, 82 R, 68 D,302, 300, 299

[56] References Cited UNITED STATES PATENTS 3,340,419 9/1967 Starr cta1. 313/70 Mar. 18, 1975 3,408,532 10/1968 Hultberg et a1 315/12 PrimaryExaminerMaynard R. Wilbur Assistant Examiner.l. M. Potenza Attorney,Agent, or Firm-Dike, Bronstein, Roberts, Cushman & Pfund [57] ABSTRACT Acold cathode discharge display apparatus in which a main electrode whoseanode consists of a plurality of electrodes while whose cathode is of aplate having a plurality of perforations for discharge space, and atrigger electrode are provided the trigger electrode consisting of afirst electrode group for column and a second electrode group for raw,whereby in the display or write operation, a voltage lower than firingvoltage but higher than a voltage for sustaining a discharge is appliedbetween the main electrodes and at the same time a drive voltage isapplied between the trigger electrodes while in the read-out operation,a voltage lower than firing voltage but higher than the voltage forsustaining the discharge is applied between the trigger electrodes.

6 Claims, 3 Drawing Figures DISGHARGE SPMIE COLD CATHODE DISCHARGEDISPLAY APPARATUS BACKGROUND OF THE INVENTION The present inventionrelates to a cold cathode discharge display apparatus, and moreparticularly to a cold cathode discharge display apparatus with memoryfunction.

A cold cathode discharge display apparatus is known in which a pluralityof discharge tubes are arranged in dots or specific patterns. In thisapparatus, desired patterns displayed by utilizing the dischargeoccurring between a pair of electrodes which are disposed in inert gassuch as argon or neon. In the conventional cold cathode dischargedisplay apparatus a plurality of display units are disposed side by sidein the envelope. Each unit consists of a plurality of segment electrodesand a counter electrode disposed to oppose the segment electrodes with apredetermined spacing therebetween. Such a display apparatus is used todisplay patterns of a plurality of digits by selectively operating thedisplay units on the time division basis at such a high speed that doesnot cause flickering.

However, because such a display device lacks memory function it isnecessary to provide an independent memory device thereby increasing thecost of manufacturing and complicating the construction of the displaydevice.

SUMMARY OF THE INVENTION Therefore, it is an object of this invention toprovide a new and improved cold cathode discharge display apparatus witha memory function without using any expensive external memory device.

Another object of this invention is to provide an improved cold cathodedischarge display apparatus capable of compact construction and ofmanifesting a memory function.

Yet another object of this invention is to provide an improved coldcathode discharge display device which is readily applicable to anassociated apparatus such as a computer in reading out the displayinformation thereof.

These and other objects, features and advantages of this invention willbecome more apparent upon a reading of the following detaileddescription and the accompanying drawings, in which;

FIG. 1 is a schematic diagram showing the operation of this invention inprinciple,

FIG. 2 is a perspective view broken away in part showing the electrodestructure of a cold cathode discharge display device according to thisinvention,

FIG. 3 shows a discharge characteristic between the main electrodes,which will aid to understand the operation of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. I, thereis shown a schematic diagram to explain the principle operation of thisinvention. A main electrode consists of a main cathode electrode a and amain anode electrode b. The main cathode electrode a is connected to oneend of a source Eu while the main anode electrode b is connected to oneend of a source Eb by way of a resistor R The other ends of the sourcesEaand Eb are connected to ground. A trigger electrode consists of atrigger anode 2 electrode X and a'trigger cathode electrode Y. Thetrigger cathode electrode Y is connected to a source terminal Eti andone terminal of a switch S1. The other terminal of the switch S1 iscoupled to ground. The

trigger anode electrode X is coupled to a source terminal Et2 and isalso connected to one terminal of a switch S2 through a resistor R2. Theswitch S2 is connected to ground at the other terminal. A properswitching means such as transistor may be employed for those switches SIand S2.

FIG. 2 illustrates an electrode arrangement ofan embodiment according tothis invention. in which a plurality of main anode electrodes 11, I2, 21and 22 are disposed at the lowermost part, a main cathode electrode a isof a plate having a plurality of perforations Ila, 12a, 21a and 22a,each of those perforations are formed so as to aligne with thecorresponding main anode electrode. One group of trigger cathodeelectrodes Y1 and Y2 are disposed under the other group of trigger anodeelectrodes X1 and X2 to form a matrix. Each of those electrodes has aplurality of perforations 11x, 11y, 12x, 12y, 21.1, 21y, 22x and 22Those perforations are prepared at the cross points of the matrix. Forexample, the perforation 12x of the trigger anode electrode X2 and theperforation 12y of the trigger cathode electrode Y1 are formed at thecross point of the cathode electrode Y1 and the anode electrode X2. Itis noted that those perforations I2.\' and 12 the perforation 12a of themain cathode electrode a and the main anode electrode 12 are aligned ina common axis, and all other perforations formed in those electrodes arealigned with the corresponding the main anode electrodes in this manner.Those perforations aligned in this way form a discharge space,respectively. Although there is no description in the drawing, it shouldbe noted that insulating material occupies the space among thoseelectrodes except the discharge space portions.

In FIG. 3, there is illustrated the change in the voltage Vp between themain anode electrode b and the main cathode electrode a when change inmade in the applied voltage therebetween, i.e. the resultant voltage Vqof the source Ea and the source Eb. The voltage Vp may be measuredbetween the point 21p and the main cathode electrode a, for example, inFIG. 1. From the FIG. 3, it may be seen that the voltage Vp increasestill the voltage E2 and suddenly decreases to the voltage Eb, as thevoltage Vq increases, while the voltage Ez does not change in the valueeven if the voltage Vq increases. That is, the Ez is a firing voltageand the Eb is a voltage for sustaining a discharge.

The operation of the embodiment of this invention will next be explainedwith above-mentioned drawings.

The operation of this invention in principle will be descriped withreference to FIG. I. The inert gas such as argon or neon is provided inthe discharge space. The resultant voltage of the sources Ea and Eb isadjusted to a voltage lower than the firing voltage but higher than thedischarge sustaining voltage. The trigger anode is impressed with avoltage higher than the firing voltage Ez while the trigger cathodeelectrode is biased with a predetermined voltage. Under this condition,when the switch S1 is closed a discharge occurs between the triggerelectrodes X and Y. This discharge exicites the inert gas in thedischarge space which in turn initiates a discharge between the mainelectrodes. The latter discharge will not cease even if the formerdischarge ceases. This is a memory function. A display is carried out bythe discharge occurring between the main electrodes. A picture elementis formed by a main anode electrode and the corresponding charge spacewhich is formed by the perforations of the main cathode electrode andthe trigger cathode and anode electrodes.

If the voltage lower than the firing voltage but higher than thedischarge sustaining voltage is impressed upon between the triggerelectrodes when the main electrodes have a discharge therebetween, thedischarge also occurs between the trigger electrodes. However, when nodischarge is performed between the main electrodes, even if such valueof voltage is impressed upon the trigger electrodes, no discharge occursbetween the trigger electrodes. As described in the above, when thedischarge occurs, the voltage between the electrodes, at the firingpoint of the discharge, will breakdown to the discharge sustainingvoltage. Consequently, if the voltage between the trigger electrodes isdetected by a proper means, it can be detected whether the mainelectrodes take a discharge or not. In FIG. 1, such detection may beperformed by measuring the voltage drop across the resistor R2.

The operation of the embodiment as shown in FIG. 2 will next bedescribed. In the display or write operation, the voltagehigher than thedischarge sustaining voltage and lower than the firing voltage isapplied between the main electrodes, and at the same time some of thetrigger electrodes forming matrix, for example, the electrodes Y1, X1and X2, are energised by an electrical signal higher than the firingvoltage E1. As a result, the discharge occurs between the main anodeelectrode 11 and the main cathode on the perforation 11a, and occursbetween the main anode electrode 12 and the main cathode electrode a atthe perforation 12a. Accordingly, the pattern formed by the twodischarge dots is obtained. Such pattern remains in display if theelectrical signal for the trigger electrodes is removed. ln other words,this pattern is at memorized state.

in read-out operation of the information of such pattern, the triggeranode electrodes X1 and X2, and the cathode electrodes, Y1 and Y2 forforming columns and raws, respectively are successively scanned with theelectrical signal of the voltage lower than the firing voltage but thedischarge sustaining voltage. As in the above description, the voltagebetween the trigger electrodes is dropped to the discharge sustainingvoltage Eb when those electrodes have the perforations corresponding tothe now discharging main electrodes. Accordingly, the read-out operationis accomplished by detecting the voltage drop. That is, in this case thevoltage drop is found between the electrodes Y1 and X1, and between theelectrodes Y1 and X2.

Having described a specific embodiment of our bearing, it is believedobvious that modification and variation of our invention is possible inlight of the above teaching.

What is claimed is:

1. A cold cathode discharge display apparatus:

a plurality of first electrodes;

second electrode having a plurality of perforations,

each of which is arranged so as to substantially confront each of saidfirst electrodes;

a plurality of third electrodes which are arranged in parallel with eachother and are oriented in the first direction, each of those electrodeshaving a plurality of perforations substantially aligned with thecorresponding said perforations of said second electrodes; and

a plurality of fourth electrodes which are arranged in parallel witheach other and are oriented in the second direction, each of thoseelectrodes having a plurality of perforations substantially aligned withthe corresponding said perforations of said third electrodes;

whereby when the voltage lower than firing voltage but higher thanvoltage for sustaining the discharge, is applied between said first andsaid second electrodes and at the same time said third and said fourthelectrodes which are properly selected, are energized by an electricalsignal, a proper pattern is formed in display.

2. A cold cathode display apparatus as claimed in claim 1, in which saidsecond electrode is formed of a plate.

3. A cold cathode display apparatus as claimed in claim 1, in which oneof said perforations of the said first, second, third and one of firstelectrodes which are arranged in common axis form a discharge space.

4. A cold cathode display apparatus as claimed in claim 1, in'which oneof said perforations of the said first. second, third and one of firstelectrodes which are arranged in common axis, form a discharge space.

5. A cold cathode discharge display apparatus; a plurality of firstelectrodes;

second electrode having a plurality of perforations, each of which isarranged so as to substantially confront each of said first electrodes;plurality of third electrodes which are arranged in parallel to eachother and are oriented in a first direction, each of those electrodeshaving a plurality of perforations substantially aligned with the corre'sponding said perforations of said second electrodes;

a plurality of fourth electrodes which are arranged in parallel to eachother and are oriented in a second direction, each of those electrodeshaving a plurality of perforations substantially aligned with thecorresponding said perforations of said third electrodes; and

a voltage detecting means to detect the voltage change between saidthird electrodes and said fourth electrodes;

whereby when the voltage lower than firing voltage but higher thanvoltage for sustaining the discharge, is applied between said first andsaid second electrodes and at the same time said third and said fourthelectrodes which are properly selected, are energized by an electricalsignal, a proper pattern is formed in display while when the voltagelower than firing voltage but higher than the discharge sustainingvoltage is applied between said third electrodes and said fourthelectrodes, a pattern in display may be detected.

6. A cold cathode display apparatus as claimed in claim 5, in which saidsecond electrode is formed of a plate.

1. A cold cathode discharge display apparatus: a plurality of first electrodes; second electrode having a plurality of perforations, each of which is arranged so as to substantially confront each of said first electrodes; a plurality of third electrodes which are arranged in parallel with each other and are oriented in the first direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said second electrodes; and a plurality of fourth electrodes which are arranged in parallel with each other and are oriented in the second direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said third electrodes; whereby when the voltage lower than firing voltage but higher than voltage for sustaining the discharge, is applied between said first and said second electrodes and at the same time said third and said fourth electrodes which are properly selected, are energized by an electrical signal, a proper pattern is formed in display.
 2. A cold cathode display apparatus as claimed in claim 1, in which said second electrode is formed of a plate.
 3. A cold cathode display apparatus as claimed in claim 1, in which one of said perforations of the said first, second, third and one of first electrodes which are arranged in common axis form a discharge space.
 4. A cold cathode display apparatus as claimed in claim 1, in which one of said perforations of the said first, second, third and one of first electrodes which are arranged in common axis, form a discharge space.
 5. A cold cathode discharge display apparatus; a plurality of first electrodes; second electrode having a plurality of perforations, each of which is arranged so as to substantially confront each of said first electrodes; a plurality of third electrodes which are arranged in parallel to each other and are oriented in a first direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said second electrodes; a plurality of fourth electrodes which are arranged in parallel to each other and are oriented in a second direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said third electrodes; and a voltage detecting means to detect the voltage change between said third electrodes and said fourth electrodes; whereby when the voltage lower than firing voltage but higher than voltage for sustaining the discharge, is applied between said first and said second electrodes and at the same time said third and said fourth electrodes which are properly selected, are energized by an electrical signal, a proper pattern is formed in display while when the voltage lower than firing voltage but higher than the discharge sustaining voltage is applied between said third electrodes and said fourth electrodes, a pattern in display may be detected.
 6. A cold cathode display apparatus as claimed in claim 5, in which said second electrode is formed of a plate. 